1. Field of the Invention
The present invention relates to chairs, particularly chairs for the lower back and exercise chairs designed to be used in strengthening the back muscles.
2. Proir Art
Many exercise devices exist for strengthening the back muscles. However, studies have shown that exercises to strengthen a particular group of muscles, whether in the back or elsewhere, have limitations because of muscle interactions. In particular, exercises for the muscles of the trunk are difficult to accomplish because of interaction of the muscles with other quite powerful muscles particularly those of the legs. Accordingly, stabilization of the pelvic region during the exercise is quite important. With particular reference to the muscles of the lower back, stabilization of the pelvis to prevent rotation thereof during an exercise routine is needed to isolate the lumbar region and provide for an acceptable exercise apparatus. None of the exercise devices in the prior art are effective in pelvic stabilization. See Peterson, et al., Comparison of the effectiveness of two pelvic stabilization systems on pelvic movement during maximal isometric trunk extension and flexion muscle contractions, Physical Therapy, 534-539 (April 1987).